- does the template attack trigger slay movement?
- does the template attack benefit from charge/fighting style/tactic/spell/talent bonuses?
- does the template attack work in tandem with Armour Knowledge?
- does the template attack allow me to place the template in contact with the bearer he is not engaging anyone?

Here's my Ideas: the 3" AOE attack is a special attack used instead of the normal attack of the bearer. so:

1.the slay movement is not triggered cause is only activate when you kill someone with a charge attack;
2. charghe and fighting style is not used for this attack cause you use it just placing the template in front of you, not after another action. for tactics, spells and other stuff, i think the bearer benefit for them just if is not mentioned, in tactic,spell, ability description, that influence normal attacks. (e.g.: the buffs of the Vølva berserk brew).
3. Just as say above, i don't thing this ability is triggered cause it say that the enemy suffer -1 DEF and ARM against melee attack originated by the Warsmith. but this is not an attack cause have not a target.
4.i think you can case, as say above, again, it's not a normal attack and is not said that touch need a target.

Ok guys, here is the official answer (new Errata is coming really soon and this issue will also be included):

1.) You are allowed to make Slay Movement if you use the AOE attack as your charge attack and the target model of the charge is killed with this attack.

2.) Like the Warsmiths tactic Chasm Cracker no bonus is applied to the rolls (except it is stated otherwise in the text of the tactic/attack). These are no melee attacks ruleswise, you only make a melee attack roll (that is the exact wording of the abilities) to see if it hits. So all tactics/spells/abilities etc. that refers to a melee attack can't be applied to abilities or tactics that make only a melee attack roll and are not stated as a melee attack (the special attack of the Doomangr Devastator is in fact defined as a AOE attack).

3.) See 2.)

4.) Since you replace your normal melee attack with the special AOE attack and you can only make a melee attack while you engage an enemy, you are not allowed to place the AOE template while not engaging an enemy model (you can only make this attack if you could have made a normal melee attack as well).

We intentionally made this wording of the affected abilities/tactics since it makes no sense to give a bonus due to knowing the weak spots of the enemies armor etc. when I just slam the hammer to the ground to create a crack or a shock wave that knock the models down or damages them. Additionally it would lead to pretty unfair situations were a hit would be almost certain no matter what the enemies DEF is and much too powerfull mass attacks (potentially 3 AOE attacks (with Slay Movement) in one round with possibly MEL 12 and POW 7 (charge bonus, armor knowledge, voelva berserker brew, strongarm ale) would definitely wipe out every unit, even Legionnaires in Testudo and would therefore be gamebreaking).

My ideas was based on the description cause in other case of different type of attack written in the description that you can choose to do a normal attack or a special kind of. for this weapon is not stated so my think was of some kind of special ability to use and not the normal attack.